1. Field of the Invention
The present invention relates to dampers and more particularly to a damping strut or vibration isolator which utilizes a compressible fluid such as air to provide pneumatic damping.
2. Description of the Prior Art
Dampers are well known in the art. Prior art dampers utilize a non-compressible fluid in a sealed container connected to a first member and forming a chamber on either side of a piston connected to a second member. A passage around or through the piston permits a predetermined flow path for the non-compressible fluid as forces cause the piston to vibrate or move in the container. A flexible chamber such as a bellows is connected to the chamber to permit fluid expansion and contraction as the temperature changes. By proper choice of the non-compressible fluid and the size of the passage around the piston, a desired resistance to motion of one of the members is provided thus damping transfer of such motions to the other member. Alternately, the container may be formed by flexible chambers on either side of the apertured piston to provide the desired damping between the members.
One disadvantage of the prior art dampers is the requirement for a fluid expansion chamber to accommodate volume changes due to temperature variations. The added size and weight are undesirable particularly in space applications where size and weight limitations are severe. Another disadvantage of the prior art dampers is that the viscosity of the non-compressible fluid changes significantly with temperature changes and such changes in viscosity alter the damping characteristics.